MySQL Cluster Manager 8.4.6 User Manual
list nextnodeids cluster_name
        MySQL Cluster Manager normally assigns IDs to new node processes automatically
        (although this can be overridden when issuing the
        create cluster or
        add process command). The
        list nextnodeids command can be used to see
        the next node ID that MySQL Cluster Manager has reserved for the next new
        process (of each possible process type) to be added to the
        cluster named cluster_name, which is
        required.
      
mcm> list nextnodeids mycluster;
+-----------+--------------+-------------+--------------------------+
| Category  | NodeId Range | Next NodeId | Processes                |
+-----------+--------------+-------------+--------------------------+
| Datanodes | 1  - 144     | 3           | ndbd, ndbmtd             |
| Others    | 145 - 255    | 149         | ndb_mgmd, mysqld, ndbapi |
+-----------+--------------+-------------+--------------------------+
2 rows in set (0.07 sec)